To all to hem it may concern Be it known that I, REINHART J. BURHEN, a citizen of the United States, and a resident of the city of St. Louis, in the State of Missouri, have invented a certain new and use: ful Improvement in Screen Frames, of which the following is a specification.

My invention relates generally to window and other screens, and more particularly to the frames thereof, my object being to provide a knock-down framewhich may be readily and quickly erected, which will be ornamental in appearance, and pleasing tov the eye, which will obviate the necessity of fastening members, corner braces, and other additional parts of this nature, which will bring about a true level between the surfaces of adjacent strips, and which will provide for the effective connection of the screen cloth.

A further object of my invention is to provide a screen frame embodying frame strips jointed at their ends, and capable of ready association and disassociation as well as the formation of strong, rigid, permanent joints in use, obviating the necessity of additional fastening means.

My invention is illustrated in the accompanying drawing which forms a part of this specification, and in which:

Figure 1 is a side elevation looking at the outer face of the screen frame adjacent one corner;

Figure 2 is a sectional view taken therethrough substantially on line 2-2 of Fig ure 1;

Figure 3 is a similar view taken therethrough substantially on line 33 of Figure 1; and

Figure 4; is a detail perspective view showing the interengaging end portions of adjacent strips in spaced relation, which forms a corner of the frame in use.

Referring now to these figures, my invention contemplates the provision of a screen frame, the several frame strips, of which one is shown at 10 and another at 11, are provided along their inner edges with reduced extensions 12 extending continuously along their entire length, said extensions having inner flat faces, as clearly seen by reference to Figure at, and having their outer faces provided with longitudinal grooves 13 and outer rounded longitudinal ribs 14 beyond the said grooves.

Each of the frame strips is further provided with undercut shoulders 15 and 16 at its inner and outer sides respectively, and adjacent the inner end of its reduced extension 12, the shoulder 15 adjacent the inner fiat face of the extension 12 being undercut by means of a longitudinal groove 17, and

the outer shoulder 16 having an inner b6V.

elecl face, both as clearly seen by reference to Figure 4.

Each frame strip is bifurcated at one end, the bifurcations being adapted to receive the extension 12 of an adjacent strip to form a corner joint, and the bifurcated extensions 18 and 19 having their extremities formed to inter-fit the undercut shoulders 15 and 16, the extremity of the extension 18, as shown in Figure 1, having a rib 20, and the extremity of the extension19 being beveled, for this purpose.

The extension 19 is also provided with an inner projection 21 to interfit that portion of the groove 13 projecting within the bifurcation, and has a lower recess 22 receiving that portion of the rib 14 projecting within the bifurcation.

Thus, the bifurcation of one end of each strip being of a shape to receive in interfitting relation the particular shaped extension of the adjacent strip, and the parts being properly proportioned, a snug binding joint will be formed by virtue of the engagement of the rib 21 within the groove 13 and between solid portions of the extension 12, while at the same time the interfitting engagement of the extremities of the bifurcated extensions 18 and 19, by their interfitting engagement with the undercut shoulders 15 and 16, will not only prevent any tendency of the strip 11 to slip longitudinally, but will in addition bring the inner and outer faces of the frame strips into desired level with one another and maintain this level throughout the life of use of the frame.

Moreover, it is apparent from Figure 1 that in addition to a tight binding joint, my invention provides a joint of pleasing appearance, particularly from the outermost side of the frame in view of the apparently unbroken extension of the grooves and ribbed faces of the extensions 12, constituting elements of ornamentation in addition to their oint forming qualities.

The inner fiat faces of the extensions 12 also form a countersunk surface on which the screen cloth, as seen at 23, may be secured, the edges of which can be extended,

into the grooves 1'7, as shown in Figure 3, in order to conceal all raw edges without the necessity of covering strips.

I claim 1. A screen frame having detachably engaging frame strips, provided along their inner edges with reduced extensions and with undercut shoulders at the inner ends of said extensions, said strips being bifurcated at one end to receive one end of the said extension of an adjacent strip, and having the extremities of their bifurcated extensions interfitting the undercut shoulder of said adjacent strip.

2. A. screen frame having detachably engaging frame strips, provided along their inner edges with reduced extensions and with undercut shoulders at the inner ends of said extensi.ons,each of said extensions having a groove along one side, and each of said strips having a bifurcation at one end receiving one end of the extension of an adjacent strip, the bifurcated extensions of each strip being formed to interfit the undercut shoulders of said adjacent strip, and one of said bifurcated extensions having a projection at its inner face to interfit the groove of the said reduced extension of said adjacent strip.

3. A screen frame having detachably engaging frame strips, each of which strips is provided with an irregularly faced extension along its inner edge and with undercut shoulders adjacent said extension, each strip having an irregularly channeled bifurcation at one end to receive one end of the extension of an adj aoent strip in interfitting relation, and having the extremities of its bifurcated extension formed to interfit the undercut shoulders of said adjacent strip.